Google have lately been praised for their chart API and my esteemed colleague Ed Eliot has a workaround for its restrictions in terms of caching and server hits.
I played around a bit with it and thought it very cool but it felt a bit clunky to add all these values to a URL when they could be in the document for those who cannot see pie charts. This is why I wrote a small script that converts data tables to charts using the API and a wee bit of JavaScript.
Using this script you can take a simple, valid and accessible data table like the following and it gets automatically converted to a pie chart.